全文获取类型
收费全文 | 646篇 |
免费 | 29篇 |
国内免费 | 1篇 |
专业分类
林业 | 25篇 |
农学 | 17篇 |
基础科学 | 2篇 |
115篇 | |
综合类 | 99篇 |
农作物 | 29篇 |
水产渔业 | 31篇 |
畜牧兽医 | 245篇 |
园艺 | 11篇 |
植物保护 | 102篇 |
出版年
2023年 | 8篇 |
2022年 | 5篇 |
2021年 | 18篇 |
2020年 | 20篇 |
2019年 | 20篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 11篇 |
2014年 | 14篇 |
2013年 | 31篇 |
2012年 | 40篇 |
2011年 | 45篇 |
2010年 | 18篇 |
2009年 | 20篇 |
2008年 | 48篇 |
2007年 | 27篇 |
2006年 | 27篇 |
2005年 | 34篇 |
2004年 | 29篇 |
2003年 | 26篇 |
2002年 | 34篇 |
2001年 | 16篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1970年 | 4篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1964年 | 2篇 |
排序方式: 共有676条查询结果,搜索用时 453 毫秒
1.
David E. Anderson Peter D. Constable Kathleen E. Yvorchuk Neil V. Anderson Guy St-Jean Linda Rock 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1994,8(3):207-211
An alpaca and a llama in late stages of gestation were evaluated for lethargy, anorexia, and recumbency. Both camelids had cloudy, white, turbid serum, elevated serum triglyceride (1564, 5658 mg/dL, respectively) and cholesterol (158, 297 mg/dL, respectively) concentrations, and ketonuria. Signs of fetal stress were evident ultrasonographically in the alpaca, and a live cria was delivered by Cesarean section performed under general anesthesia. The alpaca developed severe metabolic acidosis, hepatic lipidosis, and acute renal failure secondary to renal lipidosis and died 36 hours after admission despite medical therapy. Histopathology revealed renal and hepatic lipidosis and neutrophilic pancreatitis. The cria died 72 hours after birth. The llama responded to IV electrolyte, dextrose, and regular crystalline insulin therapy. The pregnancy was maintained, and the llama was discharged from the hospital 20 days after admission. Two months after discharge, the llama gave birth to a live, 5 kg cria. Findings of hypertriglyceridemia, hypercholesterolemia, elevated sorbitol dehydrogenase activity, metabolic acidosis, azotemia, and ketonuria occurred in these two camelids. Based on this report, camelids appear to be similar to both horses and cattle in their response to severe energy imbalances in late gestation. 相似文献
2.
Guy PA 《New Zealand veterinary journal》1984,32(6):81-84
Ollulanus tricuspus is a parasite of the stomach of domestic cats and other animals, with a worldwide distribution. It can sometimes cause severe gastritis. Fifty-five cat stomachs were examined for O.tricuspis using three techniques. O.tricuspis was found in seven stomachs (13%) from adult cats; the number of parasites recovered from individual cats ranged from 9 to 119 (mean 54). The prevalence was higher than that previously recorded in New Zealand. Repeated dilution and sedimentation of the stomach contents and mucosal washings was found to be the most reliable detection method, being positive in all of the detected infections. Pepsin/HCI digestion of the stomach mucosa detected only 71% and punch sampling of the mucosa only 29% of these infections. This contrasts with an overseas study indicating that, in heavily infected cats, these techniques are similar in sensitivity. No macroscopic lesions were seen in the stomachs of infected cats. 相似文献
3.
Weinberg AM 《Science (New York, N.Y.)》1986,232(4751):695-696
4.
Reference ranges for five parameters of blood coagulation were established in clinically normal farmed fallow deer (Dama dama) and red deer (Cervus elaphus). Storage of plasma at -15 degrees C resulted in small increases in activated partial thromboplastin time (APTT) for both species, and in the one stage prothrombin time (OSPT) of fallow deer, between days 1 and 30. These times were then stable between days 30 and 60. The fibrinogen levels of fallow deer plasma showed a small apparent increase over 60 days. These storage artefacts were not of sufficient magnitude to preclude the use of such plasma for diagnostic purposes although they could limit its use in research. Levels of fibrin/fibrinogen degradation products (FDP) were not affected by storage at -15 degrees C. Rabbit brain thromboplastin appeared adequate for OSPT determination in both species. The activated clotting time (ACT) is recommended as a field test for screening the intrinsic and common pathways of blood coagulation in deer. 相似文献
5.
The Swedish PIUS reactor and the German-American small modular high-temperature gas-cooled reactor are inherently safe-that is, their safety relies not upon intervention of humans or of electromechanical devices but on immutable principles of physics and chemistry. A second nuclear era may require commercialization and deployment of such inherently safe reactors, even though existing light-water reactors appear to be as safe as other well-accepted sources of central electricity, particularly hydroelectric dams. 相似文献
6.
Perceptions and opinions of pet owners in the United Sates about surgery,pain management,and anesthesia in dogs and cats 下载免费PDF全文
Bradley T. Simon DVM MSc DACVAA Elizabeth M. Scallan DVM MBA MS CVA CCRP Dirsko J. F. Von Pfeil DVM DACVS DECVS DACVSMR Daniel T. Boruta DVM DACVAA Rick Wall DVM DACVSMR CCRP Belle M. Nibblett DVM MVSc DACVIM O Odette DVM DACVAA Guy Beauchamp PhD Paulo V. Steagall DVM MSc PhD DACVAA 《Veterinary surgery : VS》2018,47(2):277-284
7.
Yuval Ramot Michal Steiner Netanel Amouyal Yossi Lavie Guy Klaiman Abraham J. Domb Abraham Nyska Tal Hagigit 《Journal of toxicologic pathology》2021,34(1):11
Fracture-related infections remain a leading cause of morbidity and mortality. We aimed to establish a simple contaminated radial osteotomy model to assess the efficacy of a biodegradable polymer poly(sebacic-co-ricinoleic acid) [p(SA-RA)] containing 20% w/w gentamicin. A unilateral transverse osteotomy was induced in Sprague-Dawley (SD) rats, followed by application of Staphylococcus aureus suspension over the fracture. After successfully establishing the contaminated open fracture model, we treated the rats either systemically (intraperitoneal cefuroxime), locally with p(SA-RA) containing gentamicin, or both. Control groups included non-contaminated group and contaminated groups that were either untreated or treated with the polymer alone. After 4 weeks, the bones were subjected to micro-CT scanning and microbiological and histopathology evaluations. Micro-CT analysis revealed similar changes in the group subjected to both local and systemic treatment as in the non-contaminated control group. Lack of detectable bacterial growth was noted in most animals of the group subjected to both local and systemic treatment, and all samples were negative for S. aureus. Histopathological evaluation revealed that all treatment modalities containing antibiotics were highly effective in reducing infection and promoting callus repair, resulting in early bone healing. While p(SA-RA) containing gentamicin treatment showed better results than cefuroxime, the combination of local and systemic treatment displayed the highest therapeutic potential in this model. 相似文献
8.
9.
W. Wallender J. Rhoades M. Weinberg S. Lee C. Uptain D. Purkey 《Irrigation and Drainage Systems》2002,16(4):311-326
Land retirement is ceasing irrigation withthe goal of reducing load, in general, ofdissolved constituents and, in particular,of trace elements, present in subsurfacedrainage generated from irrigated lands. Retirement is achieved through a process ofgoal setting, strategy development anddetermining effects, developing landselection criteria, implementation, andmonitoring. In this study, effects of landretirement are evaluated using hydrologic,soil and economic models as well as resultsfrom a field demonstration study. From themodeling and field monitoring, a process isdeveloped to meet the goals of a landretirement program in the San JoaquinValley of California.Potential negative effects listed for landretirement included loss of agriculturalproductivity, perhaps permanently, and lossof revenue to surrounding communities. Uncertainties included those associatedwith reuse of retired lands as wildlifehabitat, with retired-land maintenanceincluding dust control, with potentialpreservation of retired lands in reservefor future re-introduction to irrigated ordry-land agriculture, and withinstitutional changes concerning repaymentof federal and state water contracts. Benefits would accrue from economic returnto the landowner from the sale of property,the sale or lease of irrigation watersupply, the reduced cost of handlingdrainage, and allocation of freed-up waterto beneficial uses, and the reduced risk ofselenium exposure to fish and wildlife.A recommended sequential approach to selectand manage retired land is to identifyprimary objectives; formulate and implementarea-specific land retirement scenarios;measure biologic, hydrologic, soils andeconomic consequences in the short term andthe long term and manage and monitorretired lands based on dynamic biologic,hydrologic and soil conditions. 相似文献